Recovery capabilities of Xenopus laevis after exposure to Cadmium and Zinc

The present investigation evaluates the recovery capabilities of Xenopus laevis following 12days of exposure to 30μg CdL(-1) and 1000μg ZnL(-1) alone or mixed, followed by a depuration phase in laboratory conditions. Focused endpoints, which were investigated at different times of depuration, are bioaccumulation of Cd and Zn, micronucleus induction, quantification of metallothioneins (MTs), and expression of genes involved in metal toxicity mechanisms. The results show that at the end of the contamination phase, there was higher metal bioaccumulation capability and MT synthesis in remaining tissues than in the liver. An increased expression of genes involved in detoxification and oxidative stress mechanisms was observed, suggesting an additive effect of both metals and a higher Zn regulation in the liver. During the depuration phase, the results show the recovery capability of Xenopus from 7days of depuration related to metamorphosis processes, which were observed at the end of the experiment. The results confirm the relevance of the amphibian model and the complementarities between a marker of genotoxicity, MT production, bioaccumulation and transcriptional analysis in the evaluation of the ecotoxicological impact. The results also highlight the reversible effects of Cd and Zn toxicity.

Effect of bivalent human papillomavirus vaccination on pregnancy outcomes: long term observational follow-up in the Costa Rica HPV Vaccine Trial

OBJECTIVE

To examine the effect of the bivalent human papillomavirus (HPV) vaccine on miscarriage.

DESIGN

Observational long term follow-up of a randomized, double blinded trial combined with an independent unvaccinated population based cohort.

SETTING

Single center study in Costa Rica.

PARTICIPANTS

7466 women in the trial and 2836 women in the unvaccinated cohort enrolled at the end of the randomized trial and in parallel with the observational trial component.

INTERVENTION

Women in the trial were assigned to receive three doses of bivalent HPV vaccine (n=3727) or the control hepatitis A vaccine (n=3739). Crossover bivalent HPV vaccination occurred in the hepatitis A vaccine arm at the end of the trial. Women in the unvaccinated cohort received (n=2836) no vaccination.

MAIN OUTCOME MEASURE

Risk of miscarriage, defined by the US Centers for Disease Control and Prevention as fetal loss within 20 weeks of gestation, in pregnancies exposed to bivalent HPV vaccination in less than 90 days and any time from vaccination compared with pregnancies exposed to hepatitis A vaccine and pregnancies in the unvaccinated cohort.

RESULTS

Of 3394 pregnancies conceived at any time since bivalent HPV vaccination, 381 pregnancies were conceived less than 90 days from vaccination. Unexposed pregnancies comprised 2507 pregnancies conceived after hepatitis A vaccination and 720 conceived in the unvaccinated cohort. Miscarriages occurred in 451 (13.3%) of all exposed pregnancies, in 50 (13.1%) of the pregnancies conceived less than 90 days from bivalent HPV vaccination, and in 414 (12.8%) of the unexposed pregnancies, of which 316 (12.6%) were in the hepatitis A vaccine group and 98 (13.6%) in the unvaccinated cohort. The relative risk of miscarriage for pregnancies conceived less than 90 days from vaccination compared with all unexposed pregnancies was 1.02 (95% confidence interval 0.78 to 1.34, one sided P=0.436) in unadjusted analyses. Results were similar after adjusting for age at vaccination (relative risk 1.15, one sided P=0.17), age at conception (1.03, P=0.422), and calendar year (1.06, P=0.358), and in stratified analyses. Among pregnancies conceived at any time from bivalent HPV vaccination, exposure was not associated with an increased risk of miscarriage overall or in subgroups, except for miscarriages at weeks 13-20 of gestation (relative risk 1.35, 95% confidence interval 1.02 to 1.77, one sided P=0.017).

CONCLUSIONS

There is no evidence that bivalent HPV vaccination affects the risk of miscarriage for pregnancies conceived less than 90 days from vaccination. The increased risk estimate for miscarriages in a subgroup of pregnancies conceived any time after vaccination may be an artifact of a thorough set of sensitivity analyses, but since a genuine association cannot totally be ruled out, this signal should nevertheless be explored further in existing and future studies.Trial registration Clinicaltrials.gov NCT00128661 and NCT01086709.

Association between exposure to household cigarette smoking behavior and cigarette smoking in Hispanic adults: Findings from the Hispanic Community Health Study/Study of Latinos

BACKGROUND

Cigarette smoking behavior is highly determined by social influences during childhood and adolescence. This phenomenon has not been fully evaluated in the Hispanic/Latino population.

PURPOSE

To examine the association between exposure to household cigarette smoking behavior (HCSB) and adult cigarette smoking among a diverse Hispanic/Latino population living in four US urban centers. The effect of acculturation on cigarette smoking was also evaluated.

METHODS

Data from the Hispanic Community Health Study/Study of Latinos (HCHS/SOL) (n=13,231, ages 18-74years, collected between March 2008 and June 2011) were analyzed using logistic regression.

RESULTS

HCSB exposure was an independent risk factor for adult current cigarette smoking in Hispanic/Latinos (OR 1.7; 95% CI 1.4, 2.1) after controlling for relevant confounders including socio-demographic and cultural factors. Cubans and Puerto Ricans had the highest prevalence of HCSB exposure (59% and 47% respectively) and highest prevalence of current cigarette smoking (26% and 32%) compared with other Hispanic/Latino groups, (p<.01).

CONCLUSIONS

Our data suggest that exposure to HCSB in Hispanics/Latinos living in the US is an independent predictor of adult cigarette smoking, and this association appears to be strongest in Cubans and Puerto Ricans.

Abstract 4680: Efficacy of the HPV16/18 vaccine against cervical, anal, and oral HPV infection among women with and without previous HPV16/18 exposure

Background: Previous reports from the Costa Rica Vaccine Trial demonstrated strong vaccine efficacy against HPV16/18 at the cervical, anal, and oral regions separately. However, the combined “woman-level” vaccine efficacy against infections at all three anatomic sites has not been examined in women with and without previous HPV16/18 exposure.

Methods: Women aged 18-25 from the Costa Rica Vaccine Trial were randomized to be vaccinated with the HPV16/18 Vaccine (Cervarix) or a Hepatitis A vaccine at enrollment. Cervical samples were collected at every annual visit, while oral and anal samples were collected only at the four year follow-up visit. Samples were tested for alpha mucosal HPV DNA types utilizing the SPF10 PCR-DEIA-LiPA25 version 1 method. An event in the multi-site woman-level vaccine efficacy analysis (n = 4,186) was defined as a women with prevalent HPV16/18 DNA at the cervical, anal, or oral regions. Vaccine efficacies (VEs) and 95% confidence intervals (95%CIs) were computed for one-time detection of HPV16/18 in the cervical, anal, and oral regions in this intention-to-treat analysis.

Results: Four years following initial vaccination, the combined multi-site woman-level vaccine efficacy against HPV16/18 infections was 64.8%, 95%CI = 54.8-72.8. Multi-site woman-level efficacy was stronger among women without evidence of previous HPV exposure (HPV16/18 seronegative and cervical HPV16/18 DNA negative at enrollment): VE = 83.1%, 95%CI = 72.6-89.6, but was also demonstrated among women with evidence of previous HPV16/18 exposure (HPV16/18 seropositive and cervical HPV16/18 DNA negative at baseline): VE = 49.6%, 95%CI = 2.7-73.9. Further supporting the partial protection of the vaccine in previously HPV16/18-exposed women, we observed a particularly strong vaccine efficacy against HPV16/18 at more than one anatomic site (VE = 91.4%, 95%CI = 81.4-96.6). Indeed, HPV16/18-infected women were significantly less likely to be HPV16/18-infected at two or more anatomic sites in the HPV vaccine arm than the control arm (6 of 81 (7%) vs. 70 of 230 (30%), p&lt;0.01).

Discussion: This is the first study to present a combined multi-site woman-level HPV16/18 vaccine efficacy. This study found strong multi-site efficacy among those not previously exposed to cervical HPV16/18, but also suggests the vaccine may provide some protection against HPV16/18 at multiple anatomic sites among women previously exposed to HPV16/18. If confirmed, the partial protection against cervical, anal, and/or oral HPV16/18 in women previously exposed to HPV16/18 could be considered in HPV vaccination catch-up program decision-making.

Citation Format: Daniel C. Beachler, Aimee R. Kreimer, Mark Schiffman, Rolando Herrero, Sholom Wacholder, Ana Cecilia Rodriguez, Douglas R. Lowy, Carolina Porras, John T. Schiller, Silvia Jimenez, Linda Struijk, John Schussler, Allan Hildesheim, Paula Gonzalez, Costa Rica Vaccine Trial Group. Efficacy of the HPV16/18 vaccine against cervical, anal, and oral HPV infection among women with and without previous HPV16/18 exposure. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 4680. doi:10.1158/1538-7445.AM2015-4680

Metal detoxification and gene expression regulation after a Cd and Zn contamination: an experimental study on Danio rerio

This study aimed to demonstrate the recovery potential of Danio rerio after Cd and Zn contaminations. Fish demonstrated high accumulation capacities of Cd with concentrations reaching 3716.4±578.6 μg Cd/kg FW in gills after 15 d of contamination. The 75-day decontamination failed to completely eliminate Cd (93.4% and 82.2% eliminated respectively in the gills of fish exposed to Cd and Cd/Zn) whereas Zn, poorly accumulated, was quickly depurated. The fast Cd depuration in the gills likely resulted from a metal transfer to the liver. MT response was clearly correlated to the Zn contamination, while genetic responses were more pronounced in case of Cd contamination. Cd induced over-expressions of genes involved against oxidative stress (sod, sodmt), and involved in detoxification mechanisms (mt1, mt2), mitochondrial mechanisms (cox1) and DNA repair (rad51 and gadd45). Zn binary contamination with Cd was demonstrated to provide protective effects on Cd-induced toxicity in D.rerio. Results highlighted that the genetic response was metal- and tissue-dependent. The brain and the muscles showed very few genetic responses, probably due to the low bioaccumulations measured in these tissues. Conversely, genes expressed in gills and liver of fish exposed to Cd were strongly affected (sod×3 and×12, mt1×11 and ×30 at T3 respectively in gills and liver). However, after 14-30 d of depuration, genes were no longer over expressed in response to Cd contamination in gills and liver of fish exposed to Cd and Cd/Zn conditions, suggesting an gene expression regulation of fish to the residual Cd contamination.

Rationale and design of a long term follow-up study of women who did and did not receive HPV 16/18 vaccination in Guanacaste, Costa Rica

The Costa Rica Vaccine Trial (CVT) was a randomized clinical trial conducted between 2004 and 2010, which randomized 7466 women aged 18 to 25 to receive the bivalent HPV-16/18 vaccine or control Hepatitis-A vaccine. Participants were followed for 4 years with cross-over vaccination at the study end. In 2010 the long term follow-up (LTFU) study was initiated to evaluate the 10-year impact of HPV-16/18 vaccination, determinants of the immune response, and HPV natural history in a vaccinated population. Herein, the rationale, design and methods of the LTFU study are described, which actively follows CVT participants in the HPV-arm 6 additional years at biennial intervals (3 additional study visits for 10 years of total follow-up), or more often if clinically indicated. According to the initial commitment, women in the Hepatitis-A arm were offered HPV vaccination at cross-over; they were followed 2 additional years and exited from the study. 92% of eligible CVT women accepted participation in LTFU. To provide underlying rates of HPV acquisition and cervical disease among unvaccinated women to compare with the HPV-arm during LTFU, a new unvaccinated control group (UCG) of women who are beyond the age generally recommended for routine vaccination was enrolled, and will be followed by cervical cancer screening over 6 years. To form the UCG, 5000 women were selected from a local census, of whom 2836 women (61% of eligible women) agreed to participate. Over 90% of participants complied with an interview, blood and cervical specimen collection. Evaluation of comparability between the original (Hepatitis-A arm of CVT) and new (UCG) control groups showed that women's characteristics, as well as their predicted future risk for cervical HPV acquisition, were similar, thus validating use of the UCG. LTFU is poised to comprehensively address many important questions related to long-term effects of prophylactic HPV vaccines.

Genetic and physiological responses of three freshwater diatoms to realistic diuron exposures

This study examined the effects of diuron on strains of three major freshwater diatom species, Eolimna minima, Nitzschia palea and Planothidium lanceolatum. These species are frequently recorded in the Morcille River, where diuron runs off during phytosanitary treatments of the vineyards around. Here, there were three diatom exposure groups for each species: 0, 1 and 10 μg/L diuron during a 14-day laboratory assessment. Diuron water concentration, cell number, photosynthetic activity and gene expression were assessed at 6 h and 2, 7 and 14 days after contamination. Diuron exposure altered photosynthetic activity in that the optimal quantum yield of photosystem II (PSII) decreased between 40 and 50% and, for P. lanceolatum at 10 μg/L, there was complete inhibition. Genetic responses indicated diuron effects on both photosystem II and mitochondrial metabolism in all three species at both diuron exposure levels. Thus, analysis of the expression of psaA, d1, cox1, nad5 and 12s could be an early biomarker to detect pesticide pollution. Overall, this study revealed differences in diuron sensitivity among the three species: E. minima and N. palea appeared to be more tolerant than P. lanceolatum. These results suggest that the development of molecular tools, and more precisely of biomarkers, will aid in early assessment of contamination and water quality.

Reduced prevalence of vulvar HPV16/18 infection among women who received the HPV16/18 bivalent vaccine: a nested analysis within the Costa Rica Vaccine Trial

BACKGROUND

Vaccine efficacy (VE) against vulvar human papillomavirus (HPV) infection has not been reported and data regarding its epidemiology are sparse.

METHODS

Women (n = 5404) age 22-29 present at the 4-year study visit of the Costa Rica Vaccine Trial provided vulvar and cervical samples. A subset (n = 1044) was tested for HPV DNA (SPF10/LiPA25 version 1). VE against 1-time detection of vulvar HPV16/18 among HPV vaccinated versus unvaccinated women was calculated and compared to the cervix. Prevalence of and risk factors for HPV were evaluated in the control arm (n = 536).

RESULTS

Vulvar HPV16/18 VE (54.1%; 95% confidence interval [CI], 4.9%-79.1%) was comparable to cervix (45.8%; 95% CI, 6.4%-69.4%). Vulvar and cervical HPV16 prevalence within the control arm was 3.0% and 4.7%, respectively. Independent risk factors for vulvar HPV were similar to cervix and included: age (adjusted odds ratio [aOR] 0.5 [95% CI, .3-.9] ≥28 vs 22-23]); marital status (aOR 2.3 [95% CI, 1.5-3.5] single vs married/living-as-married); and number of sexual partners (aOR 3.6 [95% CI, 1.9-7.0] ≥6 vs 1).

CONCLUSIONS

In this intention-to-treat analysis, VE against vulvar and cervical HPV16/18 were comparable 4 years following vaccination. Risk factors for HPV were similar by anatomic site.

CLINICAL TRIALS REGISTRATION

NCT00128661.

Effect of different human papillomavirus serological and DNA criteria on vaccine efficacy estimates

Two trials of clinically approved human papillomavirus (HPV) vaccines, Females United to Unilaterally Reduce Endo/Ectocervical Disease (FUTURE I/II) and the Papilloma Trial Against Cancer in Young Adults (PATRICIA), reported a 22% difference in vaccine efficacy (VE) against cervical intraepithelial neoplasia grade 2 or worse in HPV-naïve subcohorts; however, serological testing methods and the HPV DNA criteria used to define HPV-unexposed women differed between the studies. We applied previously described methods to simulate these HPV-naïve subcohorts within the Costa Rica HPV16/18 Vaccine Trial and assessed how these criteria affect the estimation of VE. We applied 2 enzyme-linked immunosorbent assay (ELISA) thresholds for HPV16 and HPV18 seropositivity (8 and 7 ELISA units/mL, respectively, for PATRICIA; 54 and 65 ELISA units/mL, respectively, for FUTURE I/II (to approximate the competitive Luminex immunoassay)) and 2 criteria for HPV DNA positivity (12 oncogenic HPV types, plus HPV66 and 68/73 for PATRICIA; or plus HPV6 and 11 for FUTURE I/II). VE was computed in the 2 naïve subcohorts. Using the FUTURE I/II and PATRICIA criteria, VE estimates against cervical intraepithelial neoplasia grade 2 or worse, regardless of HPV type, were 69.0% (95% confidence interval: 40.3%, 84.9%) and 80.8% (95% confidence interval: 52.6%, 93.5%), respectively (P = 0.1). Although the application of FUTURE I/II criteria to our cohort resulted in the inclusion of more sexually experienced women, methodological differences did not fully explain the VE differences.

Detoxification and recovery capacities of Corbicula fluminea after an industrial metal contamination (Cd and Zn): a one-year depuration experiment

This study aimed to assess the recovery capacity of the freshwater bivalve Corbicula fluminea subjected to industrial metal discharges (Cd, Zn). After a 24-day exposure in a metal-contaminated river, bivalves were transferred and maintained in the laboratory for one year under metal-free conditions. Metal accumulation, metallothionein production and genetic expressions of genes involved in metal stress were studied. Results demonstrated the high persistence of Cd in tissues (only 73% eliminated after 365 days) whereas Zn was rapidly depurated. The Cd half-life was estimated around 240 days. Metallothioneins were strongly induced within the 28 first days of decontamination, then decreased by 45% after 365 days. The metal exposure of bivalves led to a significant gene induction. After 28 days, most of the genes were no longer overexpressed, suggesting that the bivalves may withstand small amounts of non-essential metals in their tissues without showing signs of detrimental effects on the tested genes.

What are the outcomes of an industrial remediation on a metal-impacted hydrosystem? A 2-year field biomonitoring of the filter-feeding bivalve Corbicula fluminea

The Riou-Mort watershed (southwest France) exhibits high metal contaminations (Cd and Zn) related to an important mining past. In this context, a remediation process has been implemented in 2007 to reduce the watershed contamination. The aim of this study was to assess the early effectiveness of the remediation process on the hydrosystem contamination state. A biomonitoring was realized over two years (2008-2010) with the filter-feeding bivalve Corbicula fluminea, exposed along a contamination gradient. Several biological parameters were monitored: (1) Cd and Zn bioaccumulation, (2) Metallothionein (MT) production as detoxification mechanism, (3) differential gene expression (cat, sod, gst, 12S, cox1, mt). The physicochemical data highlighted strong metal contamination persistence in the river water and failed to demonstrate a significant decrease of metal contamination during the 2-year monitoring. The bioaccumulation results confirmed the persistence of a water contamination despite remediation works, with maximum values measured downstream from the industrial site (Joany). The bioaccumulation increased in 2010, reaching 69.3±5.3 μg Cd g(-1) DW at Joany in July 2010, whereas it did not exceed 1.4±0.2 μg Cd g(-1) DW at the reference site throughout the biomonitoring. MT concentrations were closely related to the contamination gradient, especially at Joany, demonstrating their strong involvement in the detoxification processes. The mt gene induction was strongly correlated to the MT and metal concentrations. The gene inductions of cat, sod, gst and 12S were correlated to both the metal concentrations and the seasonal variations, especially temperatures. This suggests that environmental factors require serious consideration for the interpretation of bioaccumulation kinetics and thus for the assessment of the remediation effectiveness. Consequently, the whole results did not yet highlight strong beneficial effects of remediation work on the hydrosystem contamination state. First benefits of that process should be progressively felt, once the remediation achieved, and should grandly accelerate the decontamination process of the contaminated area.

Durable antibody responses following one dose of the bivalent human papillomavirus L1 virus-like particle vaccine in the Costa Rica Vaccine Trial

The Costa Rica HPV16/18 Vaccine Trial (CVT) showed that four-year vaccine efficacy against 12-month HPV16/18 persistent infection was similarly high among women who received one, two, or the recommended three doses of the bivalent HPV16/18 L1 virus-like particle (VLP) vaccine. Live-attenuated viral vaccines, but not simple-subunit vaccines, usually induce durable lifelong antibody responses after a single dose. It is unclear whether noninfectious VLP vaccines behave more like live-virus or simple-subunit vaccines in this regard. To explore the likelihood that efficacy will persist longer term, we investigated the magnitude and durability of antibodies to this vaccine by measuring HPV16- and HPV18-specific antibodies by VLP-ELISA using serum from enrollment, vaccination, and annual visits through four years in four vaccinated groups; one-dose (n = 78), two-doses separated by one month (n = 140), two doses separated by six months (n = 52), and three scheduled doses (n = 120, randomly selected). We also tested enrollment sera from n = 113 HPV16- or HPV18 L1-seropositive women prevaccination, presumably from natural infection. At four years, 100% of women in all groups remained HPV16/18 seropositive; both HPV16/18 geometric mean titers (GMT) among the extended two-dose group were non-inferior to the three-dose group, and ELISA titers were highly correlated with neutralization titers in all groups. Compared with the natural infection group, HPV16/18 GMTs were, respectively, at least 24 and 14 times higher among the two-dose and 9 and 5 times higher among one-dose vaccinees. Antibody levels following one-dose remained stable from month 6 through month 48. Results raise the possibility that even a single dose of HPV VLPs will induce long-term protection.

Dissecting the contribution of actin and vimentin intermediate filaments to mechanical phenotype of suspended cells using high-throughput deformability measurements and computational modeling

Mechanical cell properties play an important role in many basic biological functions, including motility, adhesion, proliferation and differentiation. There is a growing body of evidence that the mechanical cell phenotype can be used for detection and, possibly, treatment of various diseases, including cancer. Understanding of pathological mechanisms requires investigation of the relationship between constitutive properties and major structural components of cells, i.e., the nucleus and cytoskeleton. While the contribution of actin und microtubules to cellular rheology has been extensively studied in the past, the role of intermediate filaments has been scarcely investigated up to now. Here, for the first time we compare the effects of drug-induced disruption of actin and vimentin intermediate filaments on mechanical properties of suspended NK cells using high-throughput deformability measurements and computational modeling. Although, molecular mechanisms of actin and vimentin disruption by the applied cytoskeletal drugs, Cytochalasin-D and Withaferin-A, are different, cell softening in both cases can be attributed to reduction of the effective density and stiffness of filament networks. Our experimental data suggest that actin and vimentin deficient cells exhibit, in average, 41% and 20% higher deformability in comparison to untreated control. 3D Finite Element simulation is performed to quantify the contribution of cortical actin and perinuclear vimentin to mechanical phenotype of the whole cell. Our simulation provides quantitative estimates for decreased filament stiffness in drug-treated cells and predicts more than two-fold increase of the strain magnitude in the perinuclear vimentin layer of actin deficient cells relatively to untreated control. Thus, the mechanical function of vimentin becomes particularly essential in motile and proliferating cells that have to dynamically remodel the cortical actin network. These insights add functional cues to frequently observed overexpression of vimentin in diverse types of cancer and underline the role of vimentin targeting drugs, such as Withaferin-A, as a potent cancerostatic supplement.

Glutathione S-transferase L1 multiplex serology as a measure of cumulative infection with human papillomavirus

BACKGROUND

Several assays are used to measure type-specific serological responses to human papillomavirus (HPV), including the bead-based glutathione S-transferase (GST)-L1 multiplex serology assay and virus-like particle (VLP)-based ELISA. We evaluated the high-throughput GST-L1, which is increasingly used in epidemiologic research, as a measure of cumulative HPV infection and future immune protection among HPV-unvaccinated women.

METHODS

We tested enrollment sera from participants in the control arm of the Costa Rica Vaccine Trial (n = 488) for HPV16 and HPV18 using GST-L1, VLP-ELISA, and two assays that measure neutralizing antibodies (cLIA and SEAP-NA). With statistical adjustment for sampling, we compared GST-L1 serostatus to established HPV seropositivity correlates and incident cervical HPV infection using odds ratios. We further compared GST-L1 to VLP-ELISA using pair-wise agreement statistics and by defining alternate assay cutoffs.

RESULTS

Odds of HPV16 GST-L1 seropositivity increased with enrollment age (OR = 1.20 per year, 95%CI 1.03-1.40) and lifetime number of sexual partners (OR = 2.06 per partner, 95%CI 1.49-2.83), with similar results for HPV18. GST-L1 seropositivity did not indicate protection from incident infection over 4 years of follow-up (HPV16 adjusted OR = 1.72, 95%CI 0.95-3.13; HPV18 adjusted OR = 0.38, 95%CI 0.12-1.23). Seroprevalence by GST-L1 (HPV16 and HPV18, respectively) was 5.0% and 5.2%, compared to 19.4% and 23.8% by VLP-ELISA, giving positive agreement of 39.2% and 20.8%. Lowering GST-L1 seropositivity cutoffs improved GST-L1/VLP-ELISA positive agreement to 68.6% (HPV16) and 61.5% (HPV18).

CONCLUSIONS

Our data support GST-L1 as a marker of cumulative HPV infection, but not immune protection. At lower seropositivity cutoffs, GST-L1 better approximates VLP-ELISA.

Comparison of antibody responses to human papillomavirus vaccination as measured by three assays

BACKGROUND

Different assays, including the competitive Luminex immunoassay (cLIA), secreted alkaline phosphatase neutralization assay (SEAP-NA), and virus-like particle-based ELISA, are commonly used to measure antibody responses after human papillomavirus (HPV) vaccination. Direct assay comparisons aid interpretation of immunogenicity data evaluated by different assays.

METHODS

We compared cLIA to SEAP-NA and ELISA among 51 HPV16/18-vaccinated women enrolled in the Costa Rica Vaccine Trial. We tested replicate serum samples collected at months 0, 1, and 12 by HPV16/18 cLIA, SEAP-NA, and ELISA. For a subset (N = 10), we further tested month 6, 24 and 36 samples. We calculated seroprevalence estimates and Spearman rank correlation coefficients comparing cLIA to SEAP-NA and ELISA.

RESULTS

After one vaccine dose, seroprevalence by SEAP-NA and ELISA was 100% (both HPV16 and HPV18), and by cLIA was 96% (95% CI 87-100%) for HPV16 and 71% (95% CI 56-83%) for HPV18. Seroprevalence was 100% by all assays after three doses. Correlation between assays was high after one vaccine dose [cLIA/SEAP-NA ρ = 0.91 (HPV16) and ρ = 0.86 (HPV18); cLIA/ELISA ρ = 0.84 (HPV16) and ρ = 0.74 (HPV18); all p < 0.001] and remained high through month 36. Ratios of mean antibody levels to seropositivity cutoffs at month 36 were lower for cLIA than for SEAP-NA or ELISA, particularly for HPV18 (HPV18 ratio for cLIA 1.9, SEAP-NA 3.5, ELISA 3.4).

CONCLUSION

Though correlation between cLIA and SEAP-NA/ELISA is high and stable after vaccination, the assays differ in scale and sensitivity, with notable differences after one vaccine dose and for HPV18. Our results demonstrate that comparisons of antibody responses to HPV vaccination measured by different assays are approximate, and must consider biological and technical differences between assays.

Immunogenicity assessment of HPV16/18 vaccine using the glutathione S-transferase L1 multiplex serology assay

The glutathione S-transferase (GST)-L1 multiplex serology assay has favorable properties for use in clinical trials and epidemiologic studies, including low cost, high throughput capacity, and low serum volume requirement. Therefore, we evaluated the GST-L1 assay as a measure of HPV16/18 vaccine immunogenicity. Our study population included 65 women selected from the Costa Rica Vaccine Trial who received the bivalent HPV16/18 virus-like particle (VLP) vaccine at the recommended 0/1/6-month schedule. We tested replicate serum samples from months 0/1/12 (i.e., after 0/1/3 doses) by GST-L1 and 3 other commonly used serology assays, VLP-ELISA, SEAP-NA, and cLIA. We calculated the percentage of women seropositive by GST-L1 by time point and HPV type (14 HPV types), and compared GST-L1 to other assays using Spearman rank correlation coefficients. After 1 vaccine dose, seropositivity by GST-L1 was 40% each for HPV16 and HPV18, increasing to 100% and 98%, respectively, after 3 doses. Seropositivity after 3 doses ranged from 32% to 69% for HPV types 31/33/45, for which partial vaccine efficacy is reported, though increases also occurred for types with no evidence for cross-protection (e.g., HPV77). GST-L1 correlated best after 3 doses with VLP-ELISA (HPV16 and HPV18 each ρ = 0.72) and SEAP-NA (HPV16 ρ = 0.65, HPV18 ρ = 0.71) (all P < 0.001); correlation was lower with cLIA. The GST-L1 is suitable for evaluating HPV16/18 vaccine immunogenicity after 3 vaccine doses, although in contrast to other assays it may classify some samples as HPV16/18 seronegative. The assay's utility is limited for lower antibody levels such as after receipt of 1 dose.

Abstract P5-09-19: Progesterone receptor isoform A as a predictive marker of antiprogestin therapy in breast cancer: A tissue culture method to evaluate drug responsiveness

Two thirds of breast cancers express steroid hormone receptors and are susceptible to an endocrine therapy usually aimed to target the estrogen receptors (ER). There is however compelling evidence suggesting that progesterone receptors (PR) participate together with ER, modulating breast cancer growth. Based on our results obtained in an experimental breast cancer model in which antiprogestins induce complete regression of carcinomas with higher levels of PR isoform A (PR-A) than isoform B (PR-B), we propose that antiprogestins such as mifepristone (MFP) might be a possible therapeutic option for patients expressing high levels of PR-A. The goal of our study is to correlate the ratio of PR isoform expression, with the in vitro responsiveness of human breast cancer samples to MFP. Preliminary studies indicated that primary cultures of breast cancer samples overexpressing PR-A were responsive to MFP (10 nM) in vitro. However, since the rate of successful primary cultures was not encouraging (7%), we decided to develop a tissue culture assay to evaluate MFP responsiveness of breast cancer samples in vitro.

Forty five breast cancer samples obtained from the General Pacheco´s Hospital, Buenos Aires, were kept in culture medium at room temperature and in dry ice. The former were cut in slices of 100 μm using a tissue chopper usually used to slice mouse nervous tissue for short incubations, and were incubated on filters in the presence of growth medium (fetal calf serum 10%) with or without MFP (10 nM), for 48 hs at 37º C. The slices were then fixed, paraffin embedded, and processed for Ki-67 staining to evaluate proliferating cells. Frozen samples were processed for Western blotting and the ratio of both PR isoforms was determined in nuclear extracts. In 17/45 (38%) of the samples valuable information was obtained. This was related with the quality (size and amount of viable cells) of the sample. The number of Ki-67 positive cells over the total viable cells was evaluated by a pathologist (M. May) in at least six different control or MFP-treated slices. From nine cases in which the Ki-67 index in control slices doubled the value obtained in MFP-treated slices (p&lt;0.05), 8 were samples in which PR-A was higher than PR-B. MFP increased (p&lt;0.05) the Ki-67 index in one sample with higher levels of PR-B than PR-A. No significant differences were observed in the remaining cases (null, equimolar or higher levels of PR-B than PR-A). We still plan to increase the number of samples in our study. Our data suggest that the tissue culture method developed is much more efficient than the primary cultures to evaluate drug or hormone responsiveness in breast cancer tissue. The results obtained herein support the proposal of PR-A as a predictive marker of antiprogestin therapy in breast cancer patients.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P5-09-19.